/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

using System.Collections.Generic;
using System.Linq;
using Nest.Utf8Json;

namespace Nest
{
	public class TopHitsAggregate : MetricAggregateBase
	{
		private readonly IJsonFormatterResolver _formatterResolver;
		private readonly IList<LazyDocument> _hits;

		public TopHitsAggregate() { }

		internal TopHitsAggregate(IList<LazyDocument> hits, IJsonFormatterResolver formatterResolver)
		{
			_hits = hits;
			_formatterResolver = formatterResolver;
		}

		public double? MaxScore { get; set; }

		public TotalHits Total { get; set; }

		private IEnumerable<IHit<TDocument>> ConvertHits<TDocument>()
			where TDocument : class
		{
			var formatter = _formatterResolver.GetFormatter<IHit<TDocument>>();
			return _hits.Select(h =>
			{
				var reader = new JsonReader(h.Bytes);
				return formatter.Deserialize(ref reader, _formatterResolver);
			});
		}

		public IReadOnlyCollection<IHit<TDocument>> Hits<TDocument>()
			where TDocument : class =>
			ConvertHits<TDocument>().ToList().AsReadOnly();

		public IReadOnlyCollection<TDocument> Documents<TDocument>() where TDocument : class =>
			ConvertHits<TDocument>().Select(h => h.Source).ToList().AsReadOnly();
	}
}
